Integrated circuits are fabricated by processing wafers with a series of wafer fabrication tools (referred to as processing tools). Each processing tool typically performs a wafer fabrication task (referred to as a process) on the wafers according to a predefined (or predetermined) process recipe that specifies various parameters of the process. For example, IC manufacturing typically uses multiple process steps that require many process tools, both production and support related, such that IC manufacturers often focus on monitoring a process tool's hardware and associated process to ensure and maintain stability, repeatability, and yields in IC manufacturing. Such tool monitoring may be achieved by fault detection and classification (FDC) systems, which monitor tools during processing and identify faults in the tools that causes the processing to stray from that which is expected. Although existing process tool monitoring methods and systems have been generally adequate for their intended purposes, they have not been entirely satisfactory in all respects.